1. A reactor melt out-of-pile collection, split charging and retention system is characterized by comprising a melt collection device, a multi-crucible dispersing and retention device and a cooling loop;

the melt collecting device is arranged on the vertical supporting inner wall of the pressure container and comprises an inclined surface and a coaming plate which are arranged opposite to the lower end enclosure of the pressure container, and the coaming plate is folded towards the center; the melt collecting device is of a two-layer structure and comprises a lower heat insulation layer and a surface lubricating layer;

the multi-crucible dispersing and detention device is arranged at the bottom of the pile pit and comprises a central main crucible and a plurality of auxiliary crucibles; the central main crucible and the auxiliary crucible are connected through a pore passage penetrating piece; the opening of the central main crucible faces the opening of the enclosing plate;

the cooling loop is connected with the stack pit to cool the multi-crucible dispersing and retaining device in the stack pit.

2. The reactor melt off-core collection, distribution, retention system of claim 1, wherein the melt collection means is provided with a sloped buffer step having an angle of inclination of 30-60 °.

3. The reactor melt off-core collection, racking, retention system of claim 1, wherein said cooling circuit comprises a condenser and an internal refueling water tank connected to each other; the condenser and the built-in refueling water tank are respectively connected with the steam channel and the stack pit through pipelines; and cooling water in the internal replacement material water tank is injected into the pile pit, and steam enters the condenser through the steam channel to be condensed and then flows back to the built-in material changing water tank.

4. The reactor melt off-core collection, distribution, retention system of claim 3, wherein the vapor channel is disposed in a vertical wall above the melt collection device at an upward inclination of 30-60 ° and is opened by a ball valve.

5. The reactor melt out-of-core collection, distribution, retention system of claim 1, wherein the inner wall of the core pit is provided with a thermal insulation layer; the multi-crucible dispersing and retaining device is arranged on a sacrificial concrete layer laid at the bottom of the pile pit.

6. The reactor melt out-of-core collection, split charging, retention system of claim 1, wherein the central primary crucible and the secondary crucible are both high temperature resistant multi-layer composite vessels with an open top, the inner wall is of sacrificial concrete structure, the middle is of high temperature resistant structural material, the outer wall is of stainless steel structure, and the bottom is spherical.

7. The reactor melt off-core collection, distribution, retention system of claim 6, wherein the tunnel penetration is inclined from the primary crucible to the secondary crucible at an angle of no more than 30 °.

8. The reactor melt off-core collection, distribution, retention system of claim 6, wherein the tunnel penetration is refractory zirconia and has a semi-circular cross-section.

9. The reactor melt out-of-pile collection, distribution, retention system as in any one of claims 1-8, wherein an overflow channel is provided in the interior wall of the pit at a level below the edge of the sub-crucible.

Background

At present, tens of large second-generation improved nuclear power plants are under construction and operated in China, but most of the plants are not provided with an effective out-of-pile melt retention system. After the accident of the Japanese Fudao, the safety problem of the nuclear power station is more urgent particularly for the prevention and the relief of the serious accident. At present, aiming at serious accidents, the core melt cooling and retention strategies can be mainly divided into two types: 1) cooling and detention (IVR) of the melt in the pressure vessel, which is the technology that appears in loviii VVER-440 power station in finland for the earliest time and is applied to the design of AP600, AP1000, APR1400, CAP1400 (1400 MWe pressurized water reactor designed by national nuclear power technology limited) and ACP1000 (1000 MWe pressurized water reactor designed by chinese nuclear industry group and chinese euryore group in combination), because the estimation dispute of the heat flux density of the core melt loaded on the inner wall surface of RPV is large, the current mainstream international thinking is that IVR technology is not suitable for the more-opinion power reactor type, such as the reactor type above 1000 MWe; 2) outside the pressure vessel melt cooling and retention (EVR), this technology has found application in the russian VVER-1000 model and the french ANP-designed european advanced pressurized water reactor EPR model.

The core catcher is researched by a plurality of foreign related patents, such as: a patent of the university of Massachusetts in 1978, Core catcher for nuclear reactor Core meltdown containment (US-Pat4113560), which can be regarded as a design prototype of EVR; french atomic energy agency, Core catcher device (US-Pat4280872), 1981, which advanced the EVR technology to the level of engineering application; and then a plurality of core catcher patents with different principles and structures (such as US-Pat4442065, US-Pat4113560, US-Pat4342621, US-Pat 8358732 and US-Pat 6353651); in 1995, French CEA proposed a trapping scheme in which a test tube type crucible closed at one end was constructed from three layers of composite materials (MgAl 2O4, ZrO2, steel, respectively) and arranged side by side in a cluster for external cooling.

The research on the reactor core catcher is gradually increased after the introduction of a VVER nuclear power system from Russia in China, and a series of patents are successively formed, such as a large passive nuclear power plant reactor core catcher (CN201310005308.0) with bottom water injection superposition and external cooling, a large passive pressurized water reactor nuclear power plant crucible type reactor core catcher (CN201310005342.8), a large passive pressurized water reactor nuclear power plant reactor core catcher (CN201310005579.6) with a melt expansion chamber, a device (CN201310264749.2) combining the internal and external detention of the melt of the large passive nuclear power plant, a large passive pressurized water reactor nuclear power plant reactor core catcher (CN201320007203.4) with a melt expansion chamber and the like.

EVR technology has advantages over IVR in more aggressive disposal strategies and more flexible cooling, particularly in dealing with severe accidents of the larger power stack type. Compare in VVER single crucible cooling time of at least 10 months, the many crucibles formula reactor melt heap outer entrapment system that this patent provided aims at collection, partial shipment, cooling melt in the finite space to reach the purpose that high efficiency is detained.

In view of the above, the present invention is particularly proposed.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a reactor core melt out-of-core collecting, sub-packaging and detention system.

The technical scheme of the invention is as follows:

a reactor melt out-of-pile collection, split charging and retention system comprises a melt collection device, a multi-crucible dispersion and retention device and a cooling loop;

the melt collecting device is arranged on the vertical supporting inner wall of the pressure container and comprises an inclined surface and a coaming plate which are arranged opposite to the lower end enclosure of the pressure container, and the coaming plate is folded towards the center; the melt collecting device is of a two-layer structure and comprises a lower heat insulation layer and a surface lubricating layer;

the multi-crucible dispersing and detention device is arranged at the bottom of the pile pit and comprises a central main crucible and a plurality of auxiliary crucibles; the central main crucible and the auxiliary crucible are connected through a pore passage penetrating piece; the opening of the central main crucible faces the opening of the enclosing plate;

the cooling loop is connected with the stack pit to cool the multi-crucible dispersing and retaining device in the stack pit.

Further, in the above system for collecting, separately charging and retaining the reactor melt outside the reactor, the melt collecting device is provided with an inclined buffer step, and the inclined angle of the inclined buffer step is 30-60 °.

Further, the reactor melt out-of-pile collection, split charging and retention system comprises a condenser and an internal refueling water tank which are connected with each other; the condenser and the built-in refueling water tank are respectively connected with the steam channel and the stack pit through pipelines; and cooling water in the internal replacement material water tank is injected into the pile pit, and steam enters the condenser through the steam channel to be condensed and then flows back to the built-in material changing water tank.

Further, in the above system for collecting, separately charging and retaining the reactor melt outside the reactor, the steam channel is arranged on the vertical wall surface above the melt collecting device, the inclined upward angle is 30-60 degrees, and the steam channel is opened by a spherical valve.

Further, in the reactor melt out-of-pile collection, split charging and retention system, the inner wall of the pile pit is provided with a heat insulation layer; the multi-crucible dispersing and retaining device is arranged on a sacrificial concrete layer laid at the bottom of the pile pit.

Further, in the reactor melt out-of-pile collection, split charging and retention system, the central main crucible and the auxiliary crucible are both high-temperature-resistant multi-layer composite containers with openings at the upper parts, the inner wall is of a sacrificial concrete structure, the middle is made of high-temperature-resistant structural materials, the outer wall is of a stainless steel structure, and the bottom is of a spherical surface.

Further, in the above system for collecting, separately charging and retaining the reactor melt outside the reactor, the duct penetration piece is inclined from the main crucible to the auxiliary crucible at an inclination angle of not more than 30 °.

Further, in the reactor melt out-of-pile collection, split charging and retention system, the pore passage penetrating piece is made of high-temperature-resistant zirconia and has a semicircular cross section.

Furthermore, the reactor melt out-of-pile collection, split charging and retention system is provided with an overflow channel on the inner wall surface of the pile pit at the position lower than the edge of the auxiliary crucible.

The invention has the beneficial effects that:

(1) the melt collection and early-stage lubrication design is adopted, so that the amount of the melt is centralized and controllably transferred;

(2) the design of communicating the main crucible and the auxiliary crucible is adopted, so that split charging is effectively realized, the heat exchange area is increased, and the cooling time is shortened;

(3) the collecting device and the main and auxiliary crucibles are designed by adopting multilayer composite materials, so that the instantaneous thermal shock of the melt is effectively resisted, the high temperature is endured for a long time, and the structure of the body is protected from being damaged;

(4) cooling water in the pile pit can be collected by a condenser after pool boiling evaporation, so that the utilization rate of a water source is improved;

(5) the whole system adopts a three-dimensional and compact design, occupies limited space and has high resource utilization rate.

Drawings

FIG. 1 is a schematic structural view of an off-core collection, distribution and retention system for reactor melt according to the present invention;

FIG. 2 is a cross-sectional view of a smelt collection device according to the present invention;

FIG. 3 is a schematic view showing the structure of a multi-crucible dispersion retention device in the present invention;

FIG. 4 is a schematic view of a central main crucible and support structure of the present invention.

In the above drawings, 01, a pressure vessel; 02. a melt collection device; 03. a multi-crucible dispersion retention device; 04. a thermal insulation layer; 05. sacrificial concrete; 06. supporting the concrete structure by the inner wall of the pile pit; 07. an overflow channel; 08. a steam channel; 09. a ball valve; 10. a pipeline; 11. a condenser; 12. a material changing water tank is arranged inside; 13. an electrically operated valve; 14. a pipeline; 15. a safety valve; 16. a surface lubricating layer; 17. a thermal insulation layer; 18. a central main crucible; 19. a secondary crucible; 20. a tunnel penetration; 21. a support structure.

Detailed Description

Embodiments of the invention are described below with reference to the accompanying drawings:

as shown in fig. 1, the present invention provides an off-core collection, distribution and retention system for reactor melt, which comprises a melt collection device 02, a multi-crucible dispersion and retention device 03 and a cooling loop.

In order to better collect the melt which may splash in all directions after an accident, the melt collecting device 02 is arranged on the inner vertical supporting wall of the pressure vessel 01 and comprises an inclined surface and a surrounding plate which are opposite to the lower end socket of the pressure vessel 01 and are folded towards the center. As shown in fig. 2, the smelt collecting device 02 has a two-layer structure including a lower insulation layer 17 and a surface lubrication layer 16; the surface lubricating layer 16 is a hematite layer, can ensure that the fusant is smoothly transferred without blockage, and is mainly made of ferric oxide; the lower heat insulation layer 17 is made of zirconia, and can play a heat insulation role to ensure the reliability of the device under the condition of high temperature. The melt collecting device 02 is provided with an inclined buffering step, the inclination angle of the inclined buffering step is 30-60 degrees, and the mechanical impact caused by the falling of the lower end enclosure of the whole pressure vessel 01 can be borne in an accident. The longitudinal section of the melt collection device 02 is funnel-shaped to facilitate melt collection.

The multi-crucible dispersing and detention device 03 is arranged at the bottom of the pile pit and comprises a central main crucible 18 and a plurality of auxiliary crucibles 19; as shown in FIG. 3, the central main crucible 18 and the auxiliary crucible are connected by a horizontal tunnel penetration 20; the opening of the central main crucible 18 faces the opening of the shroud. The central main crucible 18 and the auxiliary crucible 19 are both high-temperature-resistant multilayer composite containers with upper openings, the inner walls are of sacrificial concrete structures, the middle parts are made of high-temperature-resistant structural materials such as silicon carbide or zirconium oxide, the outer walls are of stainless steel structures, and the bottoms are spherical surfaces. The layers are adhered and compacted by viscose or cement. In this example, the central main crucible 18 has a diameter of 3m and a height of 4m, and the sub-crucible 19 has a diameter of 1.5m and a height of 3 m.

This example comprises a central main crucible 18, which is provided with 6 through-holes at 2/3 level and is connected to the auxiliary crucibles 19, and six auxiliary crucibles 19, which are spaced apart by 0.5 m. The tunnel penetration piece 20 can be arranged or inclined from the main crucible to the auxiliary crucible 19, the inclination angle is controlled within 30 degrees, the material is high-temperature-resistant zirconia, and the cross section is semicircular.

Aiming at the heat radiation of the high-temperature melt, a heat insulation layer 04 is arranged on the inner side of the pit inner wall supporting concrete structure 06; the thermal insulation layer 04 is made of zirconia or silicon carbide. The multi-crucible dispersing and retaining device 03 is arranged on the sacrificial concrete layer 05 laid at the bottom of the pile pit. The sacrificial concrete layer 05 is used to prevent the smelt from accidentally flowing out to melt through the lower floor of the pit. In order to maintain the cooling water level, an overflow passage 07 is provided in the inner wall surface of the pit at a level lower than the edge of the sub-crucible 19. The width of the overflow channel 07 is 0.2m, the overflow channel is arranged on the inner wall surface of the pile pit at the position which is 0.1m lower than the edge of the auxiliary crucible 19, and an overflow outlet is arranged outside the pile pit. In this embodiment, in order to make the main crucible and the auxiliary crucible with spherical bottom vertically receive the melt and keep a good cooling state in the pit, the central main crucible 18 and the auxiliary crucible 19 can be supported by the support structure 21 with slightly different heights and hollow stainless steel ring columns, and the bottom of the crucible is higher than the surface of the sacrificial concrete layer 05 by 0.3m, so as to ensure that the bottom cooling water can effectively flow.

The cooling loop is connected with the stack pit for cooling by the multi-crucible dispersing and retaining device 03 in the stack pit. The cooling circuit comprises a condenser 11 and a built-in refueling water tank 12 which are connected with each other; the condenser 11 and the built-in refueling water tank 12 are respectively connected with the steam channel 08 and the stack pit through pipelines (10 and 14); and cooling water in the built-in refueling water tank 12 is injected into a stack pit, and steam enters the condenser 11 through the steam channel 08 and flows back to the built-in refueling water tank 12 after being condensed. The condenser 11 is arranged outside the containment vessel of the reactor to enhance the heat exchange effect.

In case of accident, the electric valve 13 is opened, water in the built-in refueling water tank 12 is injected into the pit by gravity, and steam flows back to the built-in refueling water tank 12 through the steam channel 08, the pipelines (10 and 14) and the external condenser 11 arranged in the containment vessel to form a cooling loop.

In fig. 1, the steam channel 08 is arranged in the vertical wall above the smelt collecting device 02, obliquely upwards at an angle of 30-60 °, preferably 45 °, and is opened by means of a ball valve 09.

In addition, the top of the pressure container 01 of the invention is provided with a safety valve 15, and the pressure can be automatically released when the steam has overpressure.

The invention adopts the design of melt collection and early lubrication, so that the amount of the melt is centralized and controllably transferred; the design of communicating the main crucible and the auxiliary crucible is adopted, so that split charging is effectively realized, the heat exchange area is increased, and the cooling time is shortened; the collecting device and the main and auxiliary crucibles are designed by adopting multilayer composite materials, so that the instantaneous thermal shock of the melt is effectively resisted, the high temperature is endured for a long time, and the structure of the body is protected from being damaged; cooling water in the pile pit can be collected by the condenser 11 after pool boiling evaporation, so that the utilization rate of a water source is improved; the whole system adopts a three-dimensional and compact design, occupies limited space and has high resource utilization rate.

It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is intended to include such modifications and variations. The above-described embodiments are merely illustrative of the present invention, and the present invention may be embodied in other specific forms or other specific forms without departing from the spirit or essential characteristics thereof. The described embodiments are, therefore, to be considered in all respects as illustrative and not restrictive. The scope of the invention should be indicated by the appended claims, and any changes that are equivalent to the intent and scope of the claims should be construed to be included therein.